1. Field of the Invention
This invention relates to an electronic service controller for temperature-controlled appliances.
2. Description of Related Art
Service controllers that inform a user of the status of various operating conditions in a temperature-controlled appliance, such as, for example, a refrigerator and/or freezer, are well known. Such service controllers provide the user with an indication of the status of sensed conditions. Thus, the user is alerted to the existence of any abnormal operating conditions of the appliance which may indicate the appliance is malfunctioning or operating inefficiently, either of which may result in such problems as loss of food quality or even spoilage.
The presence of abnormal operating conditions within the appliance may be an indication that a malfunction of the equipment within the appliance has occurred. Obviously, in such a situation, appliance manufacturers have attempted to derive apparatuses and methods to alert the user as to the existence of the malfunction so the user can contact a service technician to correct the malfunction without unnecessary delay.
For example, U.S. Pat. No. 5,546,073 to Duff discloses an alarm system for a chiller that automatically detects abnormal consumption of electric power by a compressor unit. A cooling load is computed and then an alarm limit is determined. The alarm limit is computed based on a predetermined functional relationship between the alarm limit and coding load. An alarm is generated when an electric current exceeds the computed alarm limit.
In other conventional appliance sensing and indicating systems, a visual inspection is required when an over temperature condition is determined. For example, in the refrigerator art, U.S. Pat. No. 4,834,169 to Tershak et al. disclose a controller for operating a refrigerator that may experience an abnormal temperature condition. The controller includes a temperature sensor that senses the temperature in a portion of the refrigerator compartment to detect abnormally low temperatures in another portion of the refrigerator compartment. Corrective action is taken to eliminate the abnormal condition when such a condition is detected. Essentially, a compressor is prevented from re-energizing until the compartment temperature reaches a predetermined value.
Other types of conventional systems provide an additional indication whenever an over temperature condition has existed for longer than a predetermined period of time. Some conventional systems even shutdown the appliance. For example, U.S. Pat. No. 5,454,229 to Hanson discloses a method and apparatus to monitor conditions that may result in the shutdown of a refrigerator unit by monitoring a predetermined parameter of the refrigerator unit. A predetermined value of the predetermined parameter signals a mandatory shutdown. The predetermined parameter is monitored during the mandatory shutdown when the parameter indicates a restart value, the refrigeration unit is restarted.
U.S. Pat. No. 5,460,006 to Torimitsu discloses a system to monitor numerous food storage apparatuses. A detection device detects an internal temperature of a storage cabinet. A controller emits a control signal based on a predetermined temperature and the detected internal temperature to control operation of the cooling device such that the storage cabinet is maintained at the predetermined temperature. Electric signals are output that indicate the predetermined temperature condition and detected internal temperature to a signal receiver. The monitoring system monitors the operating conditions of the respective food storage apparatuses based on the signals received by the signal receiver. However, the system does not monitor compressor run time of any of the food storage apparatuses.
Also, in conventional refrigeration storage cabinet appliances, there are several well known methods and apparatus that determine defrost time and conditions. Occasionally, various abnormalities occur due to one or more faults in the storage cabinets. Recognizing the respective natures of the abnormalities is informative in determining the reason for the faults in the storage cabinet.
Unfortunately, the various conventional appliance monitoring methods and apparatus provide difficulties in indicating to the user and/or service technician the respective nature of the various abnormalities of the appliance. As most users are not trained in the appliance service-repair field, they are unable to determine the cause of the abnormalities. Furthermore, for a service technician to ascertain what may be causing the abnormalities in the appliance would require the service technician to physically monitor the appliance for an extended period of time, which is impractical and too time/money consuming. In refrigeration storage cabinet appliances, it would benefit the service technician to know how long defrost times are, how long the compressor has been running, and the history of the cabinet during the past few days or weeks in determining the cause of any abnormalities.
An object of this invention is to overcome the above-discussed drawbacks of conventional appliance monitoring apparatus and methods.
Another object of this invention is to provide a service controller for temperature-controlled appliances that monitors the storage cabinet operational history of a refrigerator, freezer, chiller, or other such appliance. A microprocessor that runs the appliance also stores compressor run time data and correlates such to a percentage of run time over a predetermined period of time, such as, for example, an hour, a day, or even more than a week. The service controller can display the relevant information on an exterior of the appliance, download such information to a computer, relay the information to a remote location via a modem or other known or later developed information transmission device.
If the compressor run time reaches a predetermined critical value, the service controller may display an error signal on the cabinet warning that the cabinet should be inspected or possibly serviced. The service controller also eliminates any effect defrosting may have on this determination to ensure the user and/or service technician is provided with the most relevant and accurate information.